Exam 1 Flashcards
What is the wave-particle duality?
Light can be described as either a particle or a wave
These are models, not reality.
What is the significance of wave-particle duality?
It is important at very small scales
Matter and energy do not behave like they do in our macroscopic world.
What is the visible spectrum?
Light from the sun (white light) can be separated by a prism
This was first demonstrated by Isaac Newton.
What does an atomic emission spectrum represent?
Light from one particular element contains only a few wavelengths
It does not include all colors of the spectrum.
What is the formula for the energy of a photon?
E = hν
Where h = 6.626 x 10⁻³⁴ J.s.
What is the photoelectric effect?
Many metals emit electrons when electromagnetic radiation shines on their surface
The light transfers energy to the electrons.
What happens when the intensity of light is increased in the photoelectric effect?
More electrons are emitted
This is because more energy is shining on the metal.
What is the threshold frequency in the photoelectric effect?
There is a frequency below which no electrons are ejected, regardless of light intensity
This contradicts the wave theory of light.
What concept did Einstein introduce regarding light?
Light must come in packets called photons
Each photon has a definable energy.
What does the de Broglie hypothesis state?
All matter has wave properties
The wavelength can be calculated using λ = h/mv.
What does the Heisenberg Uncertainty Principle state?
You cannot measure both the position and momentum of a small particle accurately
This applies to electrons.
What is the relationship between energy levels and quantum numbers in the Bohr model?
Each energy level has a quantum number, and energies of electrons in atoms are quantized
The higher the number, the higher the energy.
What is the role of photons in electron transitions?
Photons are emitted or absorbed as electrons move between energy levels
The energy of the photons corresponds to the difference in energy levels.
What is an atomic orbital?
Regions of high probability for finding electrons
Each orbital can be described by a set of quantum numbers.
Fill in the blank: The wavelengths of light emitted by a hydrogen atom can be calculated using the _______.
Rydberg Equation
True or False: The Bohr model works for all elements.
False
It only works for hydrogen.
What is the evidence that electrons are waves?
Double slit experiment
Demonstrates wave-like behavior.
What is the significance of Schrödinger’s wave equation?
It describes the energies and probabilities of electrons
The description of an electron is called a wave function Ψ (psi).
How do absorption and emission spectra differ?
Absorption spectra show specific wavelengths absorbed, while emission spectra show wavelengths emitted
Each element has a unique spectral fingerprint.
